The present invention is based on a hand power tool comprising a housing and a driven shaft mounted in the housing so as to be rotatable but with a spindle stop that is operable to prevent the driven shaft from rotating.
Angle grinders and hand-operated circular saws are examples of known hand power tools with spindle stop. With said machines, in order to replace the tool, the driven shaft must be prevented from rotating, so that the locking screw holding the saw blade or the grinding disk in place on the driven shaft can be loosened. The spindle stop device absorbs the torque produced when the bolt is loosened.
Cylindrical locking pins typically serve as spindle stop, said cylindrical locking pins being displaced in the longitudinal direction and thereby engaging via one end with positive engagement in a part which is coupled with the driven shaft in torsion-resistant fashion, or engaging directly in the driven shaft.
The locking pins, which are supported in longitudinally displaceable fashion, pass through the housing of the hand power tools. The housing is therefore subject to a great deal of wear in the region where the locking pin passes through, e.g. when the spindle stop is actuated while the driven shaft is turning, or when an excessively high amount of release torque is applied to a retaining nut of the saw blade or grinding disk that has rusted tight. This results in an increasing amount of play between the locking pin and the guide sleeve, and it impairs the function of the spindle stop. In addition, the guide sleeve for guiding the locking pin longitudinally in the gearbox housing can become loose and expand. This can result in gear lubricant leaking out and/or dust entering along the locking pin, so that the outside of the housing becomes dirty and the moving parts inside the housing are not adequately lubricated, due to lack of lubricant.